1. Field of the Invention
The present invention relates to a power line carrier communication system in which a plurality of communication devices are arranged on a power line via which communications are performed and its communication devices, and a method for constructing a power line carrier communication system by arranging a new communication device on a power line.
2. Description of the Related Art
A power line carrier communication system is a system in which a plurality of communication devices are arranged on a power line for the communication devices to perform communications via the power line. When the system is constructed, the attaching positions of the communication devices arranged in the system are identified and managed.
In the power line carrier communication system, communications are made using a power line for feeding power rather than a communication line dedicated to communications such as normal communications via a signal line. Thus, a communication device of a communication system cannot always be arranged at a desired position. To identify its position, it is necessary to identify its position after it is arranged.
When the number of communication devices is small, an approach to manually identify the position of each communication device is effective, when the number of communication devices is large or communication devices are arranged in a wide area, the identifying task is a considerable load. In recent years, it is desired to identify the position of each communication device by using a position identification device.
As a related art position identification technique using the position identification device, there has been proposed a method for identifying the position of a communication device by using a position information detecting device separate from a communication device attached to a power line. In this method, a communication device attached to a power line has a radio communication feature previously added and a position information detecting device having a GPS (Global Positioning System) feature and a radio communication feature is brought near a communication device attached to a power line in order to identify its position. The position information detecting device uses the radio communication feature to transmit the position information identified by the GPS feature to the communication device, and the communication device transits the position information received via the radio communication feature to a management terminal via a power line (JP-A-2004-64355, FIG. 1, etc.).
In the method described in JP-A-2004-64355, it is necessary to add a radio communication feature to a communication device of a power line carrier communication system. Further, in this method, although a position identification device is used, an operator presses a button on the position information detecting device to acquire the position information at the position and the position information acquired is transmitted to the communication device, rather than automated identification of the communication device. It is thus necessary to manually identify the position of each communication device by using the position information detecting device. In case more communication devices are used or the area of the power line carrier communication system is wide, such as in case the system is constructed outdoors, the above approach is impractical.